The school I am at put money into my bank account for health insurance. Then, I got my monthly pay. I checked at the ATM machine. Everything was ok. I saw more money in my account than stated in my contract (I had to open a new account, so it was at zero to begin with). And then 2 weeks later, the same amount put in for health insurance was taken out.

What is the reason for this? Why are people putting (additional) money into my account and then taking the same amount out?